The present invention relates generally to bus communications, and more specifically to termination of a differential bus.
A typical differential bus is implemented as a line pair (true and complement) to represent a single logical variable. A differential receiver coupled to the line pair provides a logical 1 or logical 0 output depending on which of the lines has a signal driven on it.
In an exemplary bus system, the lines in the differential pair are terminated at -1.3 volts. A transmitting unit drives a logical 1 or 0 by driving a 0.7 volt signal on either the true or complement line, and doesn't drive the other. A receiving unit will respond to a voltage differential of as little as 0.15-0.20 volts.